In recent years, for a dialysis apparatus as a blood purification apparatus, there have been proposed a technology of priming, returning blood and substitution (emergency fluid infusion) using the dialysate to be supplied to a dialyzer at the time of dialysis treatment (particularly, online HDF or online HF) and a technology of utilizing the dialysate as substitution solution for online HDF or online HF treatment. For instance, PTL 1 discloses a dialysis apparatus including a dialysate supply line with one end connected to a dialysate extraction port (hereinafter referred to as an “extraction port”) formed at a predetermined part of a dialysate introduction line and the other end connected to a blood circuit (an arterial blood circuit or a venous blood circuit); and a substitution pump disposed in the dialysate supply line. When priming, returning blood and substitution (emergency fluid infusion) is performed by such a dialysis apparatus, the dialysate of the dialysate introduction line can be supplied to the blood circuit (the arterial blood circuit or the venous blood circuit) by driving the substitution pump.
Normally, in a dialysate extraction device or a dialysate supply line in which a extraction port is formed, a check valve is disposed that allows a flow of liquid from the dialysate introduction line to the blood circuit and blocks a flow of liquid from the blood circuit to the dialysate introduction line. Such a check valve makes it possible to supply the dialysate of the dialysate introduction line to the blood circuit and to prevent blood flowing through the blood circuit from entering a pipe on the dialysis device side, such as the dialysate introduction line.
PTL 1: Japanese Unexamined Patent Application Publication No. 2004-313522